Whittlin' Down the Downtime! February 17th, 2010

Ksplice at IdologicOne crucial area of focus for Idologic Networks is uptime. We prefer not to pat ourselves on the back all too often, but we do possess quite the track record when it comes to keeping our servers online. Uptime is a function of many variables and it begins on a stable datacenter foundation which is supplemented by true server-grade hardware. (IE: We don’t stuff a glorified desktop processor in our servers!) The aspect of uptime that any good System Administrator – whether he or she oversees Linux, Windows, or UNIX – grapples most fiercely with is the software side.

If you ever updated your home desktop or laptop, you know exactly what we are talking about. Upgrades to the Operating System (OS) core virtually always require a reboot. If, as with a server, your object is to stay online as much as possible, this clearly becomes counterproductive. Contrary to the advice of your Uncle Al who refuses to update his Service Pack 1 installation, good security practice requires that a high-value target like a server be up to date. Your customers demand that security from you, you demand it from us, and we demand it from ourselves.

At the very core of Linux is something called the kernel. To keep this blog post short, think of the kernel as the brain and nervous system of Linux that tells it how to operate on the server. Patching this kernel with the latest security releases has always been a source of downtime. It requires a server reboot to apply the changes, and it seems like there is always a necessary update right smack in the middle of your busiest week or newest promotion. It’s not so much a problem when the reboot can wait for late at night or off hours, but it becomes a major issue when the reboot is needed quickly.

Ksplice Uptrack is the advent of rebootless kernel upgrades. This technology has been in the pipes for some time, and the good folks here at Idologic Networks maintained a watchful eye, ready to adopt it when the technology matured. This is a capacity that Linux possesses which really gives it a major advantage over Windows servers right now.

The basic synopsis on how Ksplice works is that it takes the vendor releases and converts them into hot updates (in laymen’s terms, you could think of it as a live update). The MIT minds behind the project put out a whitepaper on the subject if you would like to go into further detail, but this is the brainchild of a couple excellent observations. They realized that the vast majority of kernel upgrades simply did not need any need code and therefore required no reboot to be applied. To make a long story short, they came up with a system where they could apply the hot updates and forego the once-required server reboot for a very long time.

This technology, Ksplice, is coming to Idologic, as we’ve already begun implementing it on many of our customers’ servers. We look forward to entering a new era of uptime sans the annoying downtime that accompanies kernel upgrades. With Ksplice, we can schedule our maintenance and begin to do away with unscheduled reboots for kernel upgrades. As always, let us know at the helpdesk if you have any questions!

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